1. Field of the Invention
The present invention relates to an optical potentiometer and an operating device including the same.
2. Description of the Related Art
Generally, an operating device such as an endoscope, a medical manipulator, and a treatment device is provided with an inserting section to be inserted in a patient's body, and to which a bendable moving section is provided. In many of such a moving section, a mechanism that is driven by traction by a linear power transmission member such as a wire is employed. In order to accurately operate the operating device, a unit to detect a bending angle of the moving section needs to be provided. However, since a diameter of the operating device is small, it is difficult to install a conventional potentiometer or encoder. Further, in a case where a freedom of the operating device is high, the number of units to detect those bending angles becomes large accompanying an increase in the number of joints, and electrical wirings to measuring sections of the detecting unit are increased. It is difficult to provide a large number of wirings between machineries and mechanisms within the thin operating device.
An optical potentiometer that does not require an electrical wiring to a measuring section is disclosed for example in Jpn. UM Appln. KOKAI Publication No. 55-40312. The optical potentiometer disclosed in the Jpn. UM Appln. KOKAI Publication No. 55-40312 includes, on a surface of a code disc that is movably supported, a read track whose transmittance varies along a moving direction of the code disc, and a light emitting head and a light receiving head that are arranged opposing one another with the read track intervened in between. This optical potentiometer measures a movement of the code disc by utilizing a change caused by the movement of the code disc in an amount of light that is radiated from the light emitting head and received by the light receiving head by transmitting the read track.